title: Niemann-pick type C2 deficiency in human fibroblasts confers robust and selective activation of prostaglandin E2 biosynthesis.
abstract: Activated fibroblasts, also known as myofibroblasts, are mediators of several major human pathologies including proliferative fibrotic disorders, invasive tumor growth, rheumatoid arthritis, and atherosclerosis. We previously identified Niemann-Pick type C2 (NPC2) protein as a negative regulator of fibroblast activation (Csepeggi, C., Jiang, M., Kojima, F., Crofford, L. J., and Frolov, A. (2011) J. Biol. Chem. 286, 2078-2087). Here we report that NPC2-deficiency leads to a dramatic up-regulation of the arachidonic acid (AA) metabolic pathway in human fibroblasts. The major enzymes in this pathway, cPLA2 type IVA, COX-2, and mPGES-1, were dramatically up-regulated at both the transcriptional and translational levels. The specific phenotypic changes resulted in a >10-fold increase in the production and secretion of a key modulator of inflammation and immunity, prostaglandin E2. More importantly, AA metabolome profiling by liquid chromatography/tandem mass-spectrometry revealed the very specific nature of prostaglandin E2 up-regulation as the other analyzed AA metabolites derived from the COX-2, cytochrome P450, 5/15-lipoxygenase, and non-enzymatic oxidative pathways were mostly down-regulated. Blocking activity of cPLA2 efficiently suppressed expression of inflammatory cytokines, IL-1β and IL-6, thereby identifying cPLA2 as an important regulator of the inflammatory program in NPC2-null cells. Altogether, these studies highlight NPC2 as a specific regulator of AA metabolism and inflammation that suggests potential for NPC2 protein or its related signaling in the treatment of inflammatory diseases characterized by the presence of activated fibroblasts.
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, University of Kentucky, Lexington, Kentucky 40536, USA. andrey.frolov@uky.edu
authors.forename: Andrey
authors.initials: A
authors.lastname: Frolov
authors.forename: Hua
authors.initials: H
authors.lastname: Dong
authors.forename: Min
authors.initials: M
authors.lastname: Jiang
authors.forename: Lihua
authors.initials: L
authors.lastname: Yang
authors.forename: Erik C
authors.initials: EC
authors.lastname: Cook
authors.forename: Rahul
authors.initials: R
authors.lastname: Matnani
authors.forename: Bruce D
authors.initials: BD
authors.lastname: Hammock
authors.forename: Leslie J
authors.initials: LJ
authors.lastname: Crofford
mesh_terms: D001172:Arthritis, Rheumatoid / Q000473:pathology; D053898:Biosynthetic Pathways / Q000187:drug effects; D002352:Carrier Proteins / Q000378:metabolism; D002853:Chromatography, Liquid; D015232:Dinoprostone / Q000096:biosynthesis*; D005347:Fibroblasts / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D006023:Glycoproteins / Q000172:deficiency* / Q000378:metabolism; D054513:Group IV Phospholipases A2 / Q000378:metabolism; D006801:Humans; D007249:Inflammation / Q000378:metabolism / Q000473:pathology; D018836:Inflammation Mediators / Q000378:metabolism; D053583:Interleukin-1beta / Q000494:pharmacology; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D018613:Microscopy, Confocal; D020411:Oligonucleotide Array Sequence Analysis; D021381:Protein Transport / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects; D013583:Synovial Membrane / Q000473:pathology; D015854:Up-Regulation / Q000187:drug effects; D033921:Vesicular Transport Proteins
chemical_list: D002352:Carrier Proteins; D006023:Glycoproteins; D018836:Inflammation Mediators; D053583:Interleukin-1beta; C104585:NPC2 protein, human; D033921:Vesicular Transport Proteins; D054513:Group IV Phospholipases A2; D015232:Dinoprostone
keywords: Arachidonic Acid; Cell Biology; Inflammation; Myofibroblast; Prostaglandins